Oxygenated derivatives of acyclic olefins

ABSTRACT

COMPOUNDS HAVING THE FORMULA   CH3-(CH2)4-C(-H)N==CH==C(-CH3)(-H)(2-N)-CH2-R   WHEREIN A DOUBLE BOND IS LOCATED IN ONE OF THE POSITIONS INDICATED BY THE DOTTED LINES AND WHEREIN R REPRESENT A -COOH OR -CH2OH GORUP AND N STANDS FOR THE INTEGER 1 OR 2; AND METHODS FOR MANUFACTURING THE SAID COMPOUNDS WHICH ARE USEFUL AS FRAGRANCES AND FIXATIVES IN THE PERFUME INDUSTRY.

United States Patent OXYGENATED DERIVATIVES F ACYCLIC OLEFINS Edouard P. Demole, Geneva, Switzerland, assignor to Firmenich & Cie, Geneva, Switzerland No Drawing. Filed Jan. 16, 1969, Ser. No. 791,770 Claims priority, application Switzerland, Jan. 17, 1968, 792/68 Int. Cl. C08h 17/36 US. Cl. 260-413 7 Claims ABSTRACT OF THE DISCLOSURE Compounds having the formula e CH3 (CH2)4 CHn=-CH=CH2-u-CH2R wherein a double bond is located in one of the positions indicated by the dotted lines and wherein R represents a COOH or CH OH group and n stands for the integer l or 2; and methods for manufactuin-g the said compounds which are useful as fragrances and fixatives in the perfume industry.

The invention relates to new oxygenated derivatives of acyclic olefins which have interesting olfactive and fixative properties and are, therefore, useful and used as fragrances and fixatives in the preparation of perfumes and perfumed products. Furthermore, the invention relates to methods for the manufacture of the said new derivatives.

The compounds of this invention correspond to the general formula wherein a double bond is located in one of the positions indicated by the dotted lines and wherein R represents a COOH or CH OH group and n stands for the integer l or 2.

The compounds of Formula I exist both in the cis and trans configurations.

The acids and alcohols represented by Formula I have been found to possess interesting odours of a surprisingly high intensity exceeding substantially the average odoriferous power of many of the common known fragrances. When added to mixtures of other odoriferous ingredients, the new compounds also exert a fixing action on these mixtures.

The compounds I develop powdery and somewhat fatty, very natural odour notes and can be used as odoriferous ingredients, fixatives or modifiers in the preparation of perfumes and perfumed products. The term perfumes includes undiluted perfume concentrates, perfume compositions diluted with solvents, such as ethyl alcohol, essential oils, and fragrant mixtures which are not finished perfumes but are used as modifiers in the preparation of finished perfumes. The term perfumed products includes soaps, detergents, cosmetic products such as creams, milks, hair lotions, toilet waters, deodorants and the like, and more generally all goods in which fragrances are incorporated in order to make them more attractive.

The proportions in which the new compounds of Formula I are used vary within wide limits depending on the particular odoriferous effects to be achieved and the type of fragrant material to be obtained. Due to their unusually high odoriferous power the acids and alcohols of Formula I can be used in extremely low concentrations, for instance of the order of about 0.05 to 0.5% of the total weight of a perfume concentrate. In certain cases it is possible to obtain noticeable odoriferous effects with proportions even lower than 0.05%, e.g., in diluted perfumes. However, higher concentrations of the new fragrances can be used, e.g., about 0.5 to 5% of the weight of a composition, when special odoriferous effects are desired. The new fragrances can also be used in the preparation of artificial essential oils such as Cassie oil.

The new compounds I, when added in small proportions, e.g. 0.05 to 0.5% to perfume compositions, prothe basic and final note of the perfumes. Moreover, the compositions, impart to the latter a more natural odoriferous character.

Since the odoriferous properties of the acids and alcohols of Formula I are similar in kind, they can be used either individually or as mixtures of two or more of them. Furthermore, since the cis and trans isomers of each of the compounds of Formula I have very similar olfactive properties it is generally advantageous to use a mixture of the two geometrical forms instead of one or the other isomer of the selected compound. Moreover, except for particular cases, the proportion of each of the geometrical isomers in the said binary mixtures has no substantial influence on the desired odour note and, consequently, it is generally more economical to use the cistrans-mixtures directly resulting from the syntheses without previously separating the cis-and trans-forms.

According to the invention a process for the preparation of compounds I with trans-configuration comprises (a) saponifying and partially hydrogenating esters of formula r'ce containing two conjugated double bonds in two of the positions indicated by the dotted lines and wherein R represents an aliphatic radical comprising from 1 to 4 carbon atoms and n stands for the integer 1 or 2, in order to obtain the compounds I wherein R is COOH, then (b) subsequently reducing the carboxylic groups of the partially hydrogenated products to obtain the compounds I wherein R is a methylol group.

Usual known methods for carrying out saponification of esters and partial hydrogenation of conjugated double bonds can be used for the saponification and the partial hydrogenation of the esters II. It is advantageous to perform both saponification and partial hydrogenation nearly simultaneously and to operate in an aqueous-organic medium. Thus, for instance, both operations can be carried out in a mixture of ethanol or methanol and water. The saponification can be carried out by means of a mineral alkali such as NaOH, KOH or sodium carbonate. The partial hydrogenation can be carried out for example by means of an amalgam of mercury and of an alkali metal. Sodium amalgam is preferably used. The methods just described should not be deemed as limitative whatsoever. Thus, other methods for carrying out the partial hydrogenation can also be used, for instance catalytic hydrogenation over Pd/C catalyst [see for instance, H.O. House, Modern Synthetic Reactions, W. A. Benjamin Inc., New York (1965)].

For the reduction of the carboxylic group of the partially hydrogenated products, i.e. the olefinic acids included in Formula I, usual known methods can be used; see for instance Modern Synthetic Reactions, W. A. Benjamin Inc., New York (1965). This reduction is prefgracllaly carried out by means of lithium-aluminum hy- In the process described above the double bond isomers of the compounds of Formula I wherein R represents either the group-COOH or the groupCH OH can be separated from each other by fractionation according to usual methods.

The starting material 11 used in the process described thereabove can be prepared by known methods [see for instance Tetrahedron 22, 293 (1966); J. Prakt. Chemie 284, 50 (1960); Chem. Rev. 61, 607 (1961)] according to the following reaction scheme:

According to the invention a process for the preparation of the trans compound of formula comprises oxidising 3-methyl-4-decen-1-al by means of an oxidising agent. Oxidising agents commonly used for oxidising aldehydes to the corresponding carboxylic acids can be used. The oxidation is preferably carried out by means of silver nitrate in aqueous alkaline solution.

The 3-methyl-4-decen-1-al used as a starting substance in the above process can conveniently be prepared by condensing crotonaldehyde with n-amylmagnesium bromide under Grignard reaction conditions and refluxing the resulting 2-nonen-4-ol with ethyl vinyl ether in the presence of mercuric acetate. The method described above is summarised in the following scheme:

1) condensation CH;CH=OH-OHO BrMg-(CHzh-CH;

2) hydrolysis According to the invention, a process for the preparation of those compounds of Formula I which have the double bond in the 3-position and have cis configuration comprises (a) condensing the magnesium derivative of cis-Z-bromo-Z-nonene with ethylene oxide under usual Grignard reaction conditions and (b) oxidising the resulting cis-3-methyl-3-decen-l-ol to cis-3-methyl-3-decenoic acid by means of an oxidising agent. The oxidation is preferably carried out by means of CrO (Jones reagent) although any other method normally used for oxidising unsaturated primary alcohols to the corresponding carboxylic acids can also be used.

The starting bromide used in the above process can be obtained by the reactions outlined in the following scheme:

debromodecarboxylatlon CH:\(CH2)5CHBICBIC O OH in pyridine According to the invention a process for the preparation of those compounds of Formula I which contain a double bond in the 4-position and have cis-configuration comprises (a) partially hydrogenating 3-methyl-4- decynoic acid in the presence of a poisoned hydrogenation catalyst to the corresponding olefinic acid and (b) subsequently reducing the COOH group of the olefinic acid to the corresponding methylol group. The above partial hydrogenation can be carried out in the presence, for

instance, of a Pd/C catalyst poisoned according to usual means with quinoline or lead acetate. Other methods commonly used for performing similar partial hydrogenations of triple bonds can also be used [see for example H. 0. House, Modern Synthetic Reactions, W. A. Benjamin Inc., New York (1965) p. 17 and following]. The subsequent reduction of the -COOH group is best carried out by means of lithium-aluminum hydride.

3-methyl-4-decynoic acid which is used as the starting substance in the above mentioned process can be prepared by known methods [see J. Chem. Soc. p. 39 (1946); I. Am. Chem. Soc. H, 1242 (1949)], e.g. according to the following reaction scheme:

DiEt malonatejEtON a &

The invention is further illustrated by the following examples wherein the temperatures are given in degrees centigrade.

EXAMPLE 1 A perfume composition having a Cassie-like odour was prepared by mixing the following ingredients:

Parts by Ingredients: weight Isobutyl salicylate 20 Ethyl salicylate 4 Benzyl acetate 1 Geranyl acetate 1 Eugenol at 10% 1 0.5 Ethyl phthtlate 49 Geranyl isobutyrate 0.5 Anisaldehyde 1.5 Decanal at 10% 1 0.5 Methyl Z-nonynoate at 1% 1 1.5 ,B-Ionone 1 Iris resinoid at 10% 1 5 Anisyl acetate 0.5 Benzyl alcohol 5.5 Geraniol 2 Violet leaves abs. at 1% 1 1.5 Mimosa abs. 3

1 In diethylphthalate.

By adding 1 g. of a 10% solution of 3-methyl-3-decenol 4-decenoic acid, 1 g. of 3-methyl-3-decenoic acid and 0.5 g. of a mixture of 3-methyl3-decenol and 3-methyl-4- decenol (ratio by weight about 8:2), a very tenacious natural powdery and somewhat fatty odoriferous note was imparted to the perfume composition.

EXAMPLE 2 A perfume composition of the floral type was prepared Benzyl salicylate 3 Methylnonyl acetaldehyde at 1 1 Dodecanal at 10% 1 0.5 Undecylenic aldehyde at 10% 1 1.5 Isojasmone at 10% 1 1.5 Cardamom at 1% 1 3 Santalol 1.5 Vetyveryl acetate 4.5 Exaltolide at 10% 1 (pentadecanolide) 1.5 Natural degreased civet at 10% 1 3 4 tert.Butyl 3,5 dinitro 2,6 dimethylacetophenone 6 Orange blossom abs. at 10% 1 2 Rose absolute 1 Bulgarian rose oil 1 Jasmin absolute 2 Vanillin at 1% 1 3 1 In die'thyl phthail ate.

By adding 1 g. of a 10% solution of 3-methyl-3- decenol in diethyl phthtlate to 99 g. of this mixture, the tenacity of the perfume composition was substantially improved.

EXAMPLE 3 A composition of the floral-chypre type was prepared by mixing the following ingredients:

Parts by Ingredients: weight Bergamot 6 Ylang 9 Decanal at 10% 1 0.5

Undecenal 2 Dodecanal at 10% 1 0.5 Hydroxycitronellal 6 a-Methyl p tert.-butylhydrocinnama1dehyde at 10% 1 3 Synthetic rose Synthetic jasmin 15 Tarragon at 10% 1 3 Coriander at 10% 1 1 Patchouli at 10% 1 0.5 Isobutyl salicylate 6 'y-Methylionone 6 a-Ionone 1.5 Synthetic lilac 3 Iris concrete at 1% 1 6 Decoloured oak moss absolute at 10% 1 3 Neroli bigarade 0.5 Santalol 1.5 Vetyveryl acetate 3 Oliban resinoid at 50% 1 2 Benjoin tears at 10% 1 1.5 Coumarin 1.5 Bulgarian rose oil 1.5 Jasmin absolute 1 1 In diethyl phth'alate.

By adding 0.5 g. of 3-methyl-3-decenoic acid to 99.5 g. of this mixture, a perfume composition having a more natural and tenacious scent was obtained.

EXAMPLE 4 (a) Preparation of a mixture of methyl 3-methyl- 2,4- decadien-l-oate and methyl 3-methyl-3,5-decad1enl-oate A laboratory vessel was equipped with a reflux condenser and a dropping funnel containing a mixture of 81 g. of methyl 3-methyl-4-bromocrotonate and 52 g. of trimethyl phosphite. A fraction of ml. of this mixture was poured into the vessel and heated to 90, at which temperature the reaction started. The heat source was removed, and the remainder of the liquid was introduced at such a rate that the reaction proceeded at 90 to 110. A temperature of 120 was maintained for an additional 1% hours, then distillation yielded 56.4 g. (60.5%) of dimethyl 2-methyl-3-methoxycarbonyl-allyl-phosphonate. 14 g. of sodium amide (in the form of a 50% dispersion in toluene) were suspended in 150 ml. of anhydrous tetrahydrofuran at 15-20 under nitrogen. A mixture of 17.5 g. of n-hexanal and 39 g. of the phosphonate as prepared above was added dropwise. Stirring was continued for 1 hour at 25 and for 1 hour at 50, whereupon the whole was allowed to stand overnight at room temperature. 50 ml. of a saturated NaCl solution were introduced between 0 and 10, and then three extractions with hexane were carried out. The extract was washed twice with a saturated NaCl solution, dried and distilled. There were obtained 20.47 g. (60%), B.P. 6466/0.001 torr., of a mixture of diene esters which was analysed by gas chromatography (235, 15% silicone oil, column 7.5 m.) and comprised the following fractions: (1) 35% of methyl 3-methyl- 2,4-decadienoate, cis-structure of the double bond at C2. NMR spectrum: 1.82 p.p.m., 3H (vinylic methyl); 7.56 p.p.m., 1H, d., J=15 c.p.s. (vinyl proton). (2) 15% of methyl-3,5-decadienoate. NMR spectrum: 1.97 p.p.m., 3H (vinylic methyl); 3.06 p.p.m., 2H (protons at C-2). (3) 50% of methyl 3-methyl-2,4-decadienoate, trans-structure of the double bond at C2. NMR spectrum: 2.25 p.p.m., 3H (vinylic methyl). The above mixture was thus composed of a total of 85% of methyl 3-methyl-2,4-decadienoate (mixture of cis and trans) and of 15% of 3,5- diene ester.

(b) Preparation of 3-methyl-3-decenoio acid and 3- methyl-4-decenoic acid I (R: -COOH) 30 g. of the mixture of esters prepared according to paragraph (a) of this example, 75 ml. of ethanol and 300 ml. of N caustic soda were heated to the boil until a clear solution was obtained (about 1 /2 hours). The solution was cooled to 0, and 689 g. of 2% sodium amalgam were introduced portionwise over a period of 4 hours. The solution was stirred for 3 hours at 0, then the mercury was separated and the mixture was acidified by means of 10% sulphuric acid. It was extracted three times with ether, the extracts were washed three times with water and then, after the usual treatment, they were distilled to give 22.2 g. (78.5%) of a mixture of acids which could be separated by gas chromatography (200, 5% Carbowax, column 2.5 m.) and which was composed of the following fractions: (1) 20% of 3-methyl-4- decenoic acid, of trans-configuration, the methyl ester of which, prepared according to the usual procedures, had the following NMR spectrum: 0.83-1.11 p.p.m., 6H, m.; 1.28 p.p.m. 6H, m.; 1.73.0 p.p.m., 5H, m.; 3.58 p.p.m., 3H, s.; 5.34 p.p.m., 2H, m. (2) of 3-methyl-3- decenoic acid of trans-configuration, the methyl ester of which, prepared according to the usual procedures, had the following NMR spectrum: 0.89 p.p.m., 3H, t.; 1.30 p.p.m., 8H, m.; 1.65 p.p.m., 3H, s.; 2.0 p.p.m., 2H, m,; 2.88 p.p.m., 2H, s.; 3.63 p.p.m., 3H, s.; 5.22 p.p.m., 1H, t., J =7 c.p.s. The value of 1.65 p.p.m. (vinylic methyl) is characteristic for the trans-stereoisomerism. Indeed, for the corresponding cis-ester, prepared from the corresponding cis-acid (see Example 9 hereinafter), a value of 1.76 p.p.m. was found for the resonance of the protons of the vinylic methyl.

EXAMPLE 5 Preparation of 3-methyl-3-decenol and 3-methyl-4- decenol (trans-configuration) A suspension of 1.3 g. of lithium-aluminium hydride in 80 ml. of anhydrous ether was heated to reflux temperature. A solution containing 5 g. of the mixture of acids, prepared according to paragraph (b) of Example 4, in 55 ml. of anhydrous ether was introduced dropwise. Heating was continued for /2 hour, then the usual treatment was performed to obtain 3.2 g., B.P. 7071/0.001 torr, of a substance having the following properties: n =1.4538; d =0.9532.

Analysis.Calculated for C H O (percent): C, 77.6; H, 13.02. Found (percent): C, 77.7; H, 12.80.

This product contained the following fractions (separated according to usual methods): (1) 80% of 3-methyl-3-decenol of trans-configuration the NMR spectrum of which was as follows: 0.88 p.p. m., 3H, T.; 1.28 p.p.m., 8H, s. (large); 160 p.p.m., 3H, s.; 1.75-2.50 p.p.m., 5H, m.; 3.52 p.p.m., 2H, t., 1:6.5 c.p.s.; 5.12 p.p.m., 1H, t., J =7 c.p.s.; (the isomeric cis-compound [see Example 9, paragraph showed the resonance corresponding to the protons of the vinylic methyl at 1.70 p.p.m.). (2) 20% of trans-3-methyl-4-decenol.

EXAMPLE 6 (a) Preparation of 3-n0nyn-2-ol 215 g. of ethyl bromide were added dropwise at reflux temperature to a suspension of 48.6 g. of activated Mg in 500 ml. of anhydrous ether. Heating was continued for 1 hour, then it was allowed to stand overnight at 20".

A solution of 202 g. of l-heptyne in 200 ml. of anhydrous ether was introduced under nitrogen and at reflux temperature. Refluxing was continued for 3 hours and, after cooling to -15", a solution of 92 g. of acetaldehyde in 150 ml. of anhydrous ether was introduced dropwise; the temperature was maintained between -15 and After standing for 2 days at 20 the whole was poured onto 1 litre of a 20% Nl-I Cl solution containing ice. The organic phase was separated and the aqueous phase was extracted four times with ether. The combined extracts were washed with water and after drying and distillation there were obtained 216.6 g. (78%) of 3-nonyn-2-ol, B.P. 94/ 13 torr.

(b) Preparation of 2-bromo-3-nonyne 153 g. of phosphorus tribromide were added dropwise, while stirring vigorously at room temperature to a solution containing 216 g. of 3-nonyn-2-ol prepared according to paragraph (a) of this example 450 ml. of anhydrous ether and 2.8 g. of dry pyridine. After 2 hours at reflux temperature the cooled ethereal layer was separated and poured onto a mixture of ice and water. It was extracted 3 times with ether, the combined extracts were washed 4 times with aqueous 5% Na CO then twice with brine, whereupon they were dried and distilled. There were thus obtained 177.8 g. (57%) of Z-bromo- 3-nonyne, B.P. 88-93/11 torr.

(c) Preparation of ethyl 3-nonyn-2-y1-malonate 160 g.-of diethyl malonate were added at 50 within 30 minutes, with stirring, to a solution of sodium ethoxide in ethanol (20.7 g. of Na, 760 ml. of ethanol). After heating to reflux temperature 177.8 g. of 2-bromo-3- nonyne, prepared according to paragraph (b) of this example were added dropwise. After refluxing overnight with stirring and concentration in vacuo the residue was poured onto 500 ml. of water. It was extracted 4 times with ether and after washing the combined extracts 4 times with water they were dried and distilled. There were thus obtained 165.6 g. (67%) of ethyl 3- nonyn-2-yl-malonate, B.P. 103-106/0.001 torr.

(d) Preparation of 3-methyl-4-decyn-1-oic acid 300 ml. of water, 82 g. of KOH and 165 g. of diethyl 3-nonyn-2-yl-malonate, prepared according to paragraph (c) of this example, were refluxed for 16 hours. After concentration in vacuo the residue was extracted with ether, ice was added thereto and it was acidified with aqueous HCl. It was extracted 3 times with ether and after the usual treatment of the extracts there were obtained by concentration 161 g. of an oily material which gradually solidified. This solid was taken up in petroleum ether (boiling range 30-50"), and 80 g. (60.5%) of 3-nonyn-2-yl-malonic acid, M.P. 61-63, were obtained.

This acid was heated to 150 until the evolution of gas ceased. After cooling, the residue was distilled and 53.6 g. (83%) of 3-methyl-4-decynoic acid, B.P. 113- 118/0.00l torr, having the following characteristics were obtained; n =1.4535; d =0.938l.

Analysis. Calculated for C H O (percent): C, 72.49; H, 9.96. Found (percent): C, 72.28; H, 9.77.

(e) Preparation of cis-3-methyl-4-decen-I-oic acid 150 ml. of anhydrous ethyl acetate, 3 g. of deactivated carbon-palladium catalyst, prepared according to Helv. Chim. Acta, 35, 446 (1952), and 15 g. of the acetylenic acid prepared according to paragraph (d) of this example were charged into a vessel adapted for catalytic hydrogenations. The hydrogention of this mixture was carried out according to usual methods over 24 hours whereby 5 g. of catalyst were added after 8 hours and after 16 hours of stirring. The catalyst was separated according to usual methods, then the liquid phase was concentrated and distilled. There were thus obtained 11.8 g. (78%) of cis 3 methyl-4-decen-1-oic acid, B.P. -88/0.001 torr, having the following characteristics: n =1.4473; d =0.911 6.

Analysis. Calculated for C H O (percent): C, 71.69; H, 10.94. Found (percent): C, 71.63; H, 10.72.

NMR spectrum: 0.90-1.08 ppm, 6H, m.; 1.30 p.p.m., 6H, m.; 1.80-2.40 p.p.m., 2H, m.; 2.23 p.p.m., 2H, d., J=7 c.p.s.; 2.60-3.60 p.p.m., 1H, m.; 4.80-5.50 ppm, 2H, m.; 11.93 p.p.m. 1H, s.

EXAMPLE 7 Preparation of trans-3-methyl-4-decenoic acid (a) 2-nonen-4-ol.-Magnesium turning (activated with iodine) (133.5 g.) were suspended in 1-2 litres of etherand a solution of 755.5 g. of n-amylbromide in 1.5 litres of ether was added dropwise at reflux temperature. The addition was completed within 1% hours. The mixture was refluxed for one hour, then it was cooled and a solution of 350.5 g. of crotonaldehyde in 1 litre of ether was added dropwise. The addition took 1%. hours and during this period the reaction course was controlled by cooling. After 2 hours stirring at room-temperature, the product was decomposed by the addition of a solution of 750 g. NH C1 in 2 litres of ice-water. The ether was decanted and the water phase extracted twice with ether. During the extraction operations, the formation of foam was broken down with a few drops of 10% HCl. The extracts were treated as usual and gave after final distillation 529.5 g. (74.5%)

Analysis. Calculated for C H O (percent): C, 75.99; H, 12.76. Found (percent): C, 75.88; H, 12.55.

(b) 3 methyl 4 decenal.-1n an argon atmosphere, 525 g. of 2-nonen-4-ol prepared according to the method of the previous paragraph were boiled 3 days with 2.6 litres of ethyl vinyl ether and 52.5 g. of mercuric acetate. The excess of ethyl vinyl ether was distilled off at atmosphere pressure and the residue was heated for 30 minutes at -160. After cooling, the residue was diluted with 2 litres of petroleum ether (B.P. 30-50) and the mercury salt was filtered oif. The solution was concentrated under reduced pressure and the analysis of the residue by vapour phase chromatography showed that 60% of the starting alcohol had reacted. Hence the product obtained consisted of a mixture of the wanted aldehyde and about 40% of unreacted alcohol; it was used as such in the following operations.

The pure aldehyde was prepared by Si0 column chromatography of a sample of the above mixture, using benzene as eluant. n =1.4418; d =0.8361.

Analysis. Calculated for C H O (percent): C, 78.51; H, 11.98. Found (percent): C, 79.17; H, 11.91.

(c) 3 methyl 4 decenoic acid-Under an atmosphere of argon, cis-3-methy1-4-decenal (2.22 mole), as

the 60% mixture obtained according to paragraph (b) above (total=3.7 moles), was introduced dropwise within /2 hour at a temperature comprised between 19 and 28 into a mixture of 863 g. of silver nitrate, 403 g. of NaOH and 0.6 litre of ethanol cooled with ice-water. When the addition was complete, the dropping-funnel used for the addition of the aldehyde was rinsed with 100 ml. of ethanol. The mixture was left aside overnight. Then the silver precipitate was removed by suction filtration and the precipitate was washed with warm water, ethanol and ether. The organic volatile components were distilled off from the mixture and the alkaline aqueous residue was extracted twice with ether. The extracts were washed twice with 10% NaOH and after the usual treatment they gave, after distillation, 90 g. of recovered 2-nonen-4-ol (see paragraphs (a) and (b) above).

The alkaline fraction (main aqueous mixture plus alkaline washing fractions) were acidified with 10% HCl and extracted with ether. The extract was treated as usual and concentrated. Before the final distillation, the residue was steam-distilled for a few minutes in order to remove some remaining volatile impurities. The final distillation of the residue gave 217.5 g. (32%) of trans-3-methyl-4- decenoic acid, B.P. 84-86/0.0001 torr. NMR spectrum (CCl 0.88 (3H, t., jumbled), 1.31 (9H, pseudo s.), 1.72 (3H, pseudo s.), 2.00 (2H, d., J=8 c.p.s.), 2.94 (2H, s.), 5.25 (1H, t., J=7 c.p.s.), 12.0 (1H, s.).

(d) Trans-3-methyl-4-decenol.50 g. of 3-methyl-4- decenoic acid prepared according to the description of previous paragraph (c) were reduced with 10.5 g. of LiAlH in 400 ml. of ether according to usual means (see Example 5). This reduction gave 40 g. (87.1%) of trans- 3-methyl-4-decenol, B.P. 112-113/10 torr, the properties of which were identical with those of the product obtained in Example 5.

EXAMPLE 8 Preparation of cis-3-methyl-4-decenol Cis-3-methyl-4-decenoic acid (obtained by the method described in Example 6, paragraph) (e) was reduced with LiAlI-L; according to usual means (see Example 5). The title alcohol had the following properties: B.P. 6873/ 0.001 torr; n =l.4496; d =0.8256. NMR spectrum (C01,): 0.95 (2H, d., J=6 c.p.s.), 1.3 (8H, wide band), 1.72.8 (3H, wide band), 3.5 (3H, t.), 5.2 (2H, m.) IR spectrum: 740, 1050, 1640 cmf EXAMPLE 9 Preparation of cis-3-methyl-3-decenol and cis-3- methyl-3-decenoic acid (a) 2,3dibromo-Z-methylnonanoic acid.2-methyl-3- nonenoic acid (77.8 g.), prepared according to Current Science India 34 [18], 534 (1965), c.f. J. Org. Chem. 26, 4278 (1961), B.P. 115124/0.005 torr, n =1.4647, d =0.93l0, was dissolved in CS (480 ml.). At 5, 77 g. of bromine were added dropwise with stirring. The mixture was stirred 2 hours at 0 and 15 hours at 20. The solvent was removed under reduced pressure. The crude 2,3dibromo-2-methylnonanoic acid (150 g.) which was left as a residue was used without further purification.

(b) cis-2-bromo-2-nonene.The dibromo acid prepared according to the previous paragraph (150 g.) was stirred and boiled hours with 215 g. of absolute pyridine. The mixture was stirred with ice-water (1 litre) and acidified slightly with concentrated HCl. Then it was steam-distilled until 2 litres of distillate had been collected. The organic layer was separated and the water-phase was extracted twice with ether. The extracts were treated as usual and gave after concentration and distillation 65 g. (70%) of cis-2-bromo-2-nonene, B.P. 35-40/ 0.005 torr.

(c) Cis 3 methyl-3-decenol.Activated magnesium turnings (5.35 g.) were suspended in 80 ml. of dry tetrahydrofuran and were treated dropwise at 50-55" (45 minutes) with a solution of cis-2-bromo-2-nonene prepared according to paragraph (b) above (45 g.) in THF ml.). The reaction was triggered with a trace of ethyl iodide. The mixture was kept at reflux temperature for 4 hours. It was cooled down to --l5 and between 10 and 15 and a solution of ethylene oxide (19.5 g.) in tetrahydrofuran (80 ml.) was added dropwise. Stirring was continued for 30 minutes at 5 and 30 minutes at 20. The solvent was removed nearly completely under vacuum and replace-d by 200 ml. of ether. Then ml. of saturated aqueous NH Cl solution were added and after stirring vigorously for a few minutes, the ether layer was decanted. After the usual treatment, the extract gave 38 g. of crude product. The latter was distilled and the fraction boiling at 5356/ 0.001 torr (10 g.) was collected. Pure cis-3-methyl-3-decenol had the following constants: n =1.4558; d =0.8563.

Analysis.-Calculated for C H O (percent): C, 77.58; H, 13.02. Found (percent): C, 77.36; H, 12.77.

(d) Cis-3-methyl-3-decenoic acid.--A solution of the alcohol prepared according to paragraph (c) (11.5 g.) in ml. of pure acetone was treated dropwise at 0 (l /2 hour) with 20 m1. of Jones reagent [1. Chem. Soc. 39 (1946)]. The acetone was removed under reduced pressure and replaced by 500 ml. of ether. Water (50 ml.) was added and the organic phase was separated and washed 8 times with 50 ml. portions of brine. Then it was shaken with 30 ml. portions of 5% aqueous 'NaOH. The alkaline washing waters were put aside. The ether extract was again washed with brine, dried and concentrated to leave 8.1 g. of the starting alcohol which was reused in subsequent runs.

The alkaline washing fractions were acidified with HCl and extracted with ether. After the usual treatment the ether extract gave finally 2.8 g. of residue which was distilled. 1.2 g. of the title acid, B.P. 98-100/0.001 torr, 87% pure according to vapour phase chromatography was thus obtained; it contained 13% of the trans-isomer. An analytical sample was obtained by preparative vapour phase chromatography. NMR spectrum (CCl 0.87 (3H, t. jumbled), 1.30 (9H, pseudo s.), 1.78 (3H, pseudo s.), 2.00 (2H, d., J=8 c.p.s.), 2.99 (2H, s.), 5.3 (1H, t., J =6 c.p.s.), 12.07 (1H, s.).

We claim:

1. A compound selected from the group consisting of the cis and trans isomers of compounds having the formula wherein a double bond is located in one of the positions indicated by the dotted lines and wherein R represents a COOH group and n stands for the integer 1 or 2.

2. Cis-3-methyl-3-decenoic acid.

3. Trans-3methyl-4-decenoic acid.

4. A process for the preparation of trans-3-methyl-4- decenoic acid which comprises oxidising 3-methyl-4- decen-l-al by means of an agent eifective for oxidizing the unsaturated aldehyde to the corresponding acid.

5. Process according to claim 4 which comprises using silver nitrate in aqueous alkaline solution as an oxidising agent.

6. Process for the preparation of ciscompounds of formula wherein R represents a COOH group which comprises (a) condensing the magnesium derivative of cis-2- bromo-Z-nonene with ethylene oxide and (b) oxidizing the resulting cis-3-methyl-3-decen-l-ol to the corresponding cis-3-methyl-3-decenoic acid by means of an oxidizing agent effective for oxidizing unsaturated primary alcohols to the corresponding carboxylic acids.

7. Process according to claim 6 which comprises performing (a) under usual Grignard reaction conditions and (b) using CrO (Jones reagent) as an oxidising agent.

References Cited UNITED STATES PATENTS 3,053,868 9/ 1962 Schmerling et al 260--413 OTHER REFERENCES Noller: Chem. of Organic Compounds, p. 235, W. B.

LEWIS GOTTS, Primary Examiner E. G. LOVE, Assistant Examiner US. Cl. X.R.

PO-105O UNITED STATES PATENT OFFICE Patent No. 3 579 550 Dated May 18 1971 Inventor) Edouard P. Demole It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Correction correct spelling of "phthtlate" to --phthalatebefore "methyl-3,5-decadien0ate."

insert --methyl 3- (to read -methyl 3-methy1-3,5decadienoate--) change "0.9532." to --0.8532.-

change "80 g." to -80 g.--

between lines 9 and 10, insert duce an enhancing effect on the top note as well as on- 3-methyl-3-deceno1 4-decenoic acid," with --to 98 g. of this mixture of 3-methyl-4-decenoic acid,-

Signed and sealed this 11th day of January1972.

Column Line LLSEAL) A-tte t:

EDWARD 1 'I.FLETCHER,JR. Attesting Officer ROBERT GOTTSCHALK Acting Commissioner of Patents 

